Explosively actuated cable cutter



June 23, 6 M. w. WlLTERDlNK ETAL 3,

EXPLOSIVELY ACTUATED CABLE CUTTER Filed Feb. 28, 1964 Meredith W. WiHerdink Thomas E Hursen INVENTORS.

BY ATTORNEY AGENT United States Patent 3,257,724 EXPLOSIVELY ACTUATED CABLE CUTTER Meredith W. Wilterdink, Westport, Conn, and Thomas F.

Hursen, Pitcairn, Pa., assignors, by mesne assignments,

to the United States of America as represented by the Secretary of the Navy Filed Feb. 23, 1964, Ser. No. 348,923 6 Claims. (Cl. 30-428) The present invention relates to improvements in explosively actuated cable cutting tools for use underwater, and more specifically to explosively actuated cable cutters which may be reloaded underwater and used without risk of detection of the operator by personnel at the waters surface.

Prior to the present invention, the entire volume of spent gases produced by each firing of a blank cartridge in an underwater cable cutter was expelled suddenly and directly into the water, thereby producing large bubbles which, upon reaching the surface of the water, could be easily detected. Due to the fact that underwater cable cutters are often used by Navy frogmen and other persons] in situations where the presence of the operator must be concealed, it is desirable to have an underwater cable cutter with the advantages of the previous cutters and having the further advantage of being able to protect the operator from detection.

The general purpose of this invention is to provide an explosively actuated underwater cable cutter which is safe and reliable and which will operate without producing any appreciable noise, or gas leakage in order to conceal the operation of the cable cutter An object of the present invention is the provision of an explosively actuated cable cutter which may be used and reloaded underwater while concealing the presence of the operator.

Another object is to provide a cable cutter having a buoyancy chamber to reduce the weight of the cable cutter in the water.

A further object of the invention is the provision of a cable cutter having a safety blow out plug to protect the operator from injury upon malfunction of the device.

Still another object is to provide an explosively actuated cable cutter having a gas dispersing means which disperses the spent gases in a manner precluding detection at the surface of the water.

Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings wherein:

The sole figure illustrates a plan view, partially in section, of a preferred embodiment of the invention.

Referring now to the drawings, there is shown a pistolshaped tool for use in cutting cables and the like underwater, the tool having an elongated cylindrical frame 11 to which a handle portion 12 is fixedly attached. The breech end of the frame is internally threaded at 13 to accommodate a threaded closure member 14, which member has a cylindrical bore therethrough defining a chamber 15 for receiving a blank cartridge 16 used to actuate the cable cutter. The frame has an inwardly directed annular flange formed thereon to define a shoulder 17 which acts as a stop means for a cylinder sleeve 18. Sleeve 18 closely fits into the elongated cylindrical frame and is of sufficient length as to firmly seat against shoudler 17 when closure member 14 is threaded into the frame. A piston 19 is slidably fitted into sleeve 18 and has a piston rod 21 integrally formed therewith, the piston rod being of a diameter smaller than the diameter of piston 19. Piston rod 21 slidably engages an O-ring 22 seated in a groove formed in an annular flange 20 on the frame and is guided in bushing I withdrawn and replaced by a new blank cartridge.

3,257,724 Patented June 28, 1966 23 which is seated against shoulder 17. The elongated cylindrical frame 11 and cylinder sleeve 18 inserted therein form a barrel for the gun as well as a guide for movement of piston 19 and piston 21 upon firing of cartridge 16.

At the muzzle end of the device, the frame has a pair of C-shaped hooks 24, only one of which may be seen in the drawing, forming a female shear die for holding a cable 25 or other workpiece. Attached to the end of piston rod 21 by means of a pin 26 is a work engaging member, preferably a cable cutting knife 27, having a pair of oppositely disposed tongues 28 for sliding engagement with ways or guide slots 29 formed in frame 11. The knife has an arm member 31 extending radially outwardly therefrom which serves to limit the movement of the knife and piston in a direction toward the breech end of the device and also acts a a guide to facilitate the proper positioning of cable 25 within the C-shaped hooks 24. A helical spring 32 is positioned between flange 2t) and knife 27 to resiliently bias the knife against the cable.

At the breech end of the cable cutter, a firing pin 33 is provided for firing a blank cartridge 16. The firing pin is actuated by trigger 34 through a spring and sear, not shown. A bolt 35 is provided for inserting and withdrawing blank cartridges from chamber 15 and simul taneously cocking the firing mechanism. A safety catch 36 is connected to the firing mechanism to prevent accidental firing. Breech block 37 is connected to bolt 35 and is vertically reciprocated in response to manipulation of the bolt. The surfaces of breech block 37 are so machined that the sliding engagement of said surfaces with closure member 14 provides a water-tight seal when the breech block bore 38 is exposed to the atmosphere or water, in which position a spent cartirdge may be y virtue of this arrangement, the device may be reloaded underwater without permitting water to leak into the firing chamber, thereby preserving the device from corrosion and avoiding subsequent malfunction of the firing operation.

Mounted upon the exterior of frame 11 by screws 39 is an expansion tank or buoyancy chamber 41. A passage 42 formed in closure member 14 provides fluid communication between cartridge receiving chamber 15 and another passage 43 formed in frame 11. A short pipe 4-4 is sealingly connected to passage 43 and extends into expansion tank 41 to provide fluid communication therebetween. A bore 45 is formed in frame 11 and has a short pipe (not shown but similar to pipe 44) sealingly connected thereto provide fluid communication between the expansion tank and the area adjacent piston rod 21 between O-ring 22 and bushing 23 to vent into expansion tank 41 any gases which may leak past the bushing. An adapter 46 is fitted into an aperture formed in expansion tank 41 and provides a convenient mounting means for a porous filter disk 47, which may be made of ceramic material or any other'porous material capable of dispersing a gas passed therethrough into minute bubbles, which upon rising to the surface of the water are difiicult to detect. The porous disk is held in place by a split ring 48 which seats in an annular groove formed in the adapter. A check valve consisting of a spring 49 and ball 51 seats in an aperture formed in the inner wall portion of the adapter to permit gas to flow out of the expansion tank and through the filter while prohibiting flow of seawater through the filter and into the expansion tank A piston movement arresting means or buffer is provided to stop the piston and avoid excessive impact of the piston against the annular flange portion of the frame which would otherwise occur. The buffer consists of first and second spaced apart bypass ports 52 and 53 respectively formed in the cylinder sleeve to provide fluid communication between the interior of said sleeve and an annular bypass groove 54 formed in the exterior surface of said sleeve. When a cartridge 16 is detonated, piston 19 travels to the right, as viewed in the drawing and some of the high pressure gases pass from the left side of the piston through port 52, groove 54, and port 53 back into the cylinder to the right side of piston 19 during the interval when the piston is traveling between ports 52 and 53. Further travel of the piston closes port 53, thereby trapping and compressing the gas on the right side of the piston and stopping the piston without the production of an excessive impact.

The piston and piston rod have an axial bore 55 formed therein extending longitudinally thereof to establish fluid communication with a radial bore 56 formed in the piston rod on the muzzle end of the rod. Bore 55 is closed at its piston end by a frangible plug 57 constructed of a material which ruptures under high pressures. The plug is designed to rupture in situations where the strength of the cable is abnormally high and prevents penetration of the cable by the knife. In such circumstances, when the piston cannot move under the influence of the gas pressure generated by the exploded cartridge, plug 57 will rupture to vent the gases through bores 55 and 56 and thereby relieve the pressure on the piston and avoid the danger of having the gun blow up in the operatofis hand.

The operation of the device is simple and reliable and works as follows: As illustrated in the drawing, the cable is in position for severing by the knife and a blank cartridge is in the firing position. Actuation of the trigger operates the firing pin to explode the cartridge. The expanding gas formed by the discharge of the cartridge forces the piston down the barrel and consequently moves the knife to sever the cable. A portion of the gas is diverted through the bypass ports 52 and 53 to act as a buffer and stop the piston. At this point, all of the gase generated by the cartridge are trapped within the cylinder sleeve 18 because the cartridge casing seals passage 42 to confine the gas. When bolt 35 is operated, the breech mechanism withdraws the cartridge casing from chamber 15 into breech block bore 38, thus opening passage 42 and permitting the gases to vent into the expansion tank, from which the ases pass slowly through the check valve and porous filter. While passing through the porous filter, the gases are broken up into minute bubbles which rise to the surface in that form, being free of detection by ersonnel at the surface. Further movement of bolt 35 causes the breech block to slide vertically along member 14, securing a water-tight seal at the entrance of chamber 15 before chamber 38 is exposed to the water. With the breech block in this position, the spent cartridge may be withdrawn and a new blank cartridge inserted. Manipulation of the bolt back to its original position reloads the device and restores the parts to their positions illustrated in FIG. 1. Due to the fact that the knife is biased against the cable by spring 32 and that the piston and piston rod are positively connected to the knife, the volume of the cylinder between piston 19 and member 14 is varied inversely with respect to the diameter of the cable. This enables utilization of maximum explosive force to out large diameter cables and automatically reduces the effective explosive force when small cables are being cut.

Various modifications of the device may be made. The expansion tank may be provided with any desired number of porous filter elements and the volume of the expansion tank may be selectively altered so that its buoyant force is varied to give the device a desired weight in the water and thereby enable ease of handling the device. It is also apparent that the device may be readily modified to incorporate a cartridge containing clip or magazine so that repeated firing without reloading is made possible; and the knife may be replaced by other tool forms to perform work functions other than cutting.

Obviously other modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. An explosively actuated work tool for use underwater comprising a frame having a cylindrical barrel formed therein,

a piston slidably positioned within said barrel,

a work engaging member attached to said piston and extending beyond one end of said barrel,

said frame having an explosive cartridge receiving chamber formed at the other end of said barrel,

a firing mechanism mounted on said frame for detonation of a blank cartridge in said chamber,

means for loading and reloading blank cartridges into said chamber,

a hollow expansion tank mounted on said frame and having porous filter means forming a portion of one wall of said tank for dispersing gases into the ambient water in the form of minute bubbles,

said tank having an aperture formed in one well theresaid frame having a bore formed therein extending from the exterior of said frame to intersect said cartridge receiving-chamber, and

means sealingly connecting said aperture to said bore.

2. The device of claim 1 further comprising an adapter,

said tank having an opening in one wall thereof,

said adapter being mounted in said opening and having an aperture formed therein to define a seat for a check valve seated therein,

means for mounting said porous filter in said adapter exteriorly of said check valve,

and means to bias said check valve in a direction to permit fiow out of said tank and prevent flow through the check valve into said tank.

3. An explosively actuated underwater cable cutter comprising a frame having a bore formed therein,

a female shear die formed on one end of said frame,

a piston slidably positioned in said bore and having a knife attached thereto for sliding engagement with guide means formed in said frame,

means defining a blank cartridge receiving chamber at the other end of said frame and being in fluid communication with said bore,

a trigger and firing mechanism mounted on said frame for selective firing of blank cartridges to generate high pressure gases in said bore and actuate said knife,

9. bolt mechanism for extracting fired cartridge casings and exposing said cartridge chamber for insertion of fresh blank cartridges,

a hollow buoyancy tank mounted on said frame and having an aperture in one wall thereof,

said frame having a bore therein extending from the exterior of said frame to said chamber,

means for sealingly connecting said aperture with said bore,

and porous filter means mounted in one wall of said hollow buoyancy tank for dispersing spent gases into the ambient water in the form of minute bubbles.

4. The device of claim 3 further comprising a check valve in said tank for permitting fiow through said filter only in a direction out of said tank.

5. An explosively actuated cable cutter for use underwater comprising a frame having a bore formed therein,

a cylinder sleeve fixedly positioned in said bore, said sleeve having first and second spaced apart bypass ports formed therein and having a groove formed in the outer surface thereof which provides fluid communication between first and second ports,

a piston slidably positioned in said cylinder sleeve,

a knife in sliding engagement with guide means formed in said frame,

a piston rod of smaller diameter than said piston connected at one end to said piston and at the other end to said knife,

a pair of C-shaped hooks formed on one end of said frame to define a female shear die for cooperation with said knife,

bias means in said frame to resiliently urge said knife against a cable to be cut,

means defining a blank cartridge receivingchamber at the other end of said frame and being in fluid communication with said bore,

a firing mechanism mounted on said frame for firing a blank cartridge in said chamber thereby generating high pressure gases in said bore to actuate said knife,

a hollow expansion and buoyancy tank mounted on 'said frame,

said tank having an aperture formed in one wall theremeans in said frame for providing fluid communication 6 between said aperture and said cartridge receiving chamber, and a porous filter mounted in one wall of said tank which disperses a gas passed therethrough into minute 5 bubbles.

6. The device of claim 5 further comprising a check valve mounted within said tank adjacent said porous filter and controlling all the fiow therethrough, said check valve being biased to prevent 10 flow through the check valve into said tank.

References Cited by the Examiner UNITED STATES PATENTS 2,017,329 10/1935 Temple.

2,132,148 10/1938 Davis. 2,716,813 9/1955 Smyres 30--241 2,766,525 10/1956 Hoffman 30-228 2,810,955 10/1957 Hoffman 30228 3,060,436 10/1962 De Caro et al. 227-10 3,175,289 3/1965 Wilterdink et al 30-180 WILLIAM FELDMAN, Primary Examiner.

J. C. PETERS, Assistant Examiner. 

1. AN EXPLOSIVELY ACTUATED WORK TOOL FOR USE UNDERWATER COMPRISING A FRAME HAVING A CYLINDRICAL BARREL FORMED THEREIN, A PISTON SLIDABLE POSITIONED WITHIN SAID BARREL, A WORK ENGAGING MEMBER ATTACHED TO SAID PISTON AND EXTENDING BEYOND AN EXPLOSIVE CARTRIDGE RECEIVING SAID FRAME HAVING AN EXPLOSIVE CARTRIDGE RECEIVING CHAMBER FORMED AT THE OTHER END OF SAID BARREL, A FIRING MECHANISM MOUNTED ON SAID FRAME FOR DETONATION OF A BLANK CARTRIDGE IN SAID CHAMBER, MEANS FOR LOADING AND RELOADING BLANK CARTRIDGES INTO SAID CHAMBER, A HOLLOW EXPANSION TANK MOUNTED ON SAID FRAME AND HAVING POROUS FILTER MEANS FORMING A PORTION OF ONE WALL OF SAID TANK FOR DISPERSING GASES INTO THE AMBIENT WATER IN THE FORM OF MINUTE BUBBLES, SAID TANK HAVING AN APERTURE FORMED IN ONE WALL THEREOF, SAID FRAME HAVING A BORE FORMED THEREIN EXTENDING FROM THE EXTERIOR OF SAID FRAME TO INTERSECT SAID CARTRIDGE RECEIVING CHAMBER, AND MEANS SEALINGLY CONNECTING SAID APERTURE TO SAID BORE. 